Hints come out on Lolla headliners

We may have an idea of which groups will be headlining Lollapalooza this year.

The three-day festival will take place in Grant Park August 3-5.

Since Thursday, lyrics from Sigur Ros, The Black Keys, Santigold, Kimbra and Twin Shadow have all been featured in ads promoting the event.

Now, a memo has been leaked online showing what appears to be a list of performers for the festival. The list includes Black Sabbath, The Red Hot Chili Peppers, Florence and the Machine and At the Drive In.

The official announcement of the Lollapalooza lineup will be made Wednesday.